This invention relates to electrical wiring devices and particularly to unitary receptacles having multiple outlets and to mounting arrangements for such receptacles.
In Wiley U.S. Pat. No. 4,583,799, Apr. 22, 1986, there was presented a multiple outlet receptacle of which a specific embodiment disclosed has four outlets to permit four electrical appliances to be plugged in at one receptacle location. The receptacle may be used, for example, for office lighting applications where it would normally be installed in a ceiling recess fixture, such as an outlet box or concrete ring, or some other surface mounting. The receptacle is designed to have a shallow body of molded insulating material with an integral mounting flange at the rear edges of the body. Internal contact elements of the four outlets are located within the housing portion of the body and the front face has plug blade receiving apertures for communicating with the internal contact elements. A rear closing plate of insulating material is configured to fit within the back edge of the housing portion substantially flush with the mounting flange and provides a substantially planar rear surface for the entire unit.
In the exemplary receptacle of the patent, the internal contacts extend forwardly from first and second conductive plates that rest within the housing. A first conductive plate is configured as a ring and is located near the periphery of the unit while the second conductive plate is configured to fit within the aperture of the first plate and can be made from the same piece of starting material as the first plate. Each plate supports a contact element for each of the four receptacles that is aligned with a plug aperture in the front face. For a grounding receptacle, a third group of internal contact elements is included that is attached to a third conductive plate that is located on the outside, rearward, surface of the closing plate and extends through apertures within the closing plate.
The description of receptacles of the aforementioned patent is incorporated herein by reference. Such receptacles have been successful in providing compact, reliable, attractive, and easy-to-use multiple outlet receptacles, particularly in a surface mounting arrangement.
While not limited in all respects to the same exact form of receptacle as aforementioned but taking such a multiple outlet receptacle as an example, the present invention has objectives which include further variations for mounting such receptacles and particularly in embodiments which permit the flush mounting of such a receptacle, as opposed to merely surface mounting, either with a conventional outlet box or a new portable box also included as part of the present invention.
By achieving a flush mounted arrangement for an outlet box it is possible to provide such a receptacle for general household as well as commercial use in situations where otherwise cumbersome cube taps and the like have been commonly used. One such situation would be that for a television set, video cassette recorder, and a lamp, all at a common location.
One aspect of the present invention is a wiring device adapter plate that is for mounting an electrical wiring device such as a multiple outlet receptacle with an electrical outlet box. The wiring device is, generally, one having contact elements within a housing of molded insulating material that is otherwise separately usable for mounting on a surface. The adapter plate comprises a major plate portion and a rim extending around the periphery of the major plate portion and extending forward therefrom, providing a shallow recess for accommodating and matching in lateral extent a wiring device with which the adapter plate is to be used. The rim, for example, may just accommodate a flange of a multiple outlet receptacle as illustrated in the aforementioned Wiley patent and may further have an extent from front to back substantially matching that of the edge of the flange with which it is matched.
The adapter plate also includes means for facilitating the fastening of the wiring device to the adapter plate. This means may, for example, be a pair of fastener bosses, integrally molded with the rest of the plate and diagonally disposed thereon, that include fastener apertures. The adapter plate also includes means for facilitating the fastening of the adapter plate to an electrical outlet box or the like. The latter means includes fastener apertures variously located so as to permit mounting to one or more different types of electrical outlet boxes. For example, in accordance with an embodiment of the invention, the fastener apertures, provided as the means for facilitating the fastening of the adapter plate to and electrical outlet box, include apertures located for facilitating the fastening of the adapter plate to a single gang outlet box while other fastener apertures are located for facilitating the fastening of the adapter plate to a two-gang electrical outlet box of a first configuration as well as apertures for facilitating the fastening of the adapter plate to a two-gang electrical outlet box of an alternative configuration.
The major plate portion of the adapter plate has an opening therein configured to allow wiring from an outlet box to extend through the adapter plate to a wiring device when used therewith. The opening for the wiring may be, in one example, a substantially rectangular opening with a rearward extending guide wall that fits within and facilitates the location of the adapter plate with a single-gang outlet box.
Fastener bosses on the major plate portion of the adapter plate, whether for use in facilitating fastening of a wiring device to the adapter plate or for facilitating fastening of the adapter plate to an outlet box, are provided that extend upwardly from the major plate portion to a common height less than that of the rim of the adapter plate. Such fastener bosses are configured to support, in use of the adapter plate, a wiring device used therewith and, particularly, in one form of the invention, to achieve a substantially flush relationship of the mounting flange of a wiring device, as described above, with the rim surface.
A further aspect of the invention relates to a wiring device portable box for use with an electrical wiring device of the type having contact elements within a housing of molded insulating material otherwise separately usable for mounting on a surface. The portable box comprises a back and sidewalls upstanding from the back and defining a substantially rectangular box with an open front, all of molded insulating material. At least one opening is provided within the sidewalls for use as a cord passage and the portable box further includes means for facilitating the fastening of the wiring device to the portable box, such as a pair of diagonally disposed fastener bosses having fastener apertures.
The cord passages preferably include a pair of openings each having internally adjacent cord grip configurations integrally molded with the back and sidewalls of the box. Each of the cord grip configurations preferably comprises a partial cylindrical surface extending from the opening into the box for accommodating a cord in an orientation substantially parallel to the box back and a front edge at the inner end of the partial cylindrical surface extending upwardly therefrom. Additionally, the box comprises for each of the cord grip configurations, an upper clamp of separately molded insulating material that is secured thereto for retention of the cord therein against the front edge.
In one form the sidewalls of the portable box are configured to support the lateral edge of the wiring device without appreciable overlap.
Alternatively, the portable box may be configured so that the sidewalls accommodate the wiring device and that the wiring device is supported in a manner such as on fastener bosses, all similarly to that described above with respect to the adapter plate, so that a substantially flush mounting of the wiring device within the portable box may also be achieved in those instances where the wiring device includes a mounting flange. Where the wiring device does not include a mounting flange, a recessed orientation may still be desirable and may be accomplished consistent with the general aspects of the present invention. The portable box is provided with one or more openings in the back thereof for optional use in fastening of the box to an underlying support.
In accordance with another aspect of the invention the wiring device itself, namely a multiple outlet receptacle generally in accordance with the above-mentioned Wiley patent, is modified and improved by having contact elements attached to the respective conductive plates by being staked thereto, avoiding the necessity of riveting or the like as used heretofore, and also by having terminals on the back surface of the device for wiring connections that are symmetrically disposed about the center point of the back surface of the device for facilitating wiring thereto.
Additionally, a wiring device in accordance with the present invention, whether a multiple outlet receptacle or some other device is provided which comprises an insulating housing containing contact elements and having a number of wiring terminations accessible on the exterior of the housing, each of the wiring terminations comprising a screw terminal in a contact plate to which one or more of the contact elements are joined and, proximate to the screw terminal, an aperture through the contact plate for receiving a wire conductor, the plate aperture being located over a compartment within the housing bounded by one or more insulating walls integrally molded with the housing. This compartment is configured for slidably receiving a length of wire conductor to facilitate installation by use of a technique of inserting a conductor into the aperture and compartment and then wrapping a turn of the conductor around the screw terminal and tightening it. The compartment preferably has a cross-sectional dimension that is small relative to the depth of the compartment to help retain an inserted conductor therein. While such a wiring termination feature (which may be referred to as a "snub-hole" termination) is quite useful in relation to a multiple outlet receptacle of the type particularly described, it is not limited thereto.
Each of the foregoing features contribute to enhancing the flexibility of use of wiring devices, particularly multiple outlet receptacles, so that they can be applied in a greater variety of mounting arrangements with reliability and attractiveness.